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Analog Devices Inc. LTC1474IS8#PBF
- Part No.:
- LTC1474IS8#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LTC1474IS8#PBF.pdf
- Description:
- IC REG BUCK BOOST ADJ 750MA 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:1,868
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Product details
Overview
LTC1474IS8#PBF from Analog Devices (formerly Linear Technology) is a high-efficiency, low-quiescent-current step-down DC/DC converter with internal P-channel MOSFET switch, 3.3V fixed output, 8-lead SOIC package, 10µA typical no-load supply current, and 92% peak efficiency at 250mA load. It delivers regulated 3.3V output for battery-powered portable instruments and wireless modems operating from 4V to 18V input.
For engineers reviewing the LTC1474IS8#PBF datasheet, LTC1474IS8#PBF pinout, LTC1474IS8#PBF application, or LTC1474IS8#PBF equivalent, key selection criteria include its 10µA shutdown current, programmable current limit (325–400mA), 100% duty-cycle low-dropout capability, industrial temperature range (–40°C to 85°C), and compatibility with minimal external components including Schottky catch diode and 100µH inductor.
Technical Context
The LTC1474IS8#PBF employs Burst Mode™ operation to maintain regulation while minimizing quiescent current: it alternates between short energy bursts (switch on, inductor current ramp-up) and sleep cycles (switch off, capacitor supplies load). Its internal 1.23V reference compares against feedback voltage at VOUT/VFB (Pin 1), and a dedicated low-battery comparator remains active during shutdown via LBI (Pin 3) and open-drain LBO (Pin 2).
Current limiting is implemented via a 100mV threshold across an internal 5Ω sense element plus optional external RSENSE between SENSE (Pin 6) and VIN (Pin 7); peak switch current defaults to 325mA (min) with RSENSE = 0Ω. The 4.75µs off-time is dynamically extended up to 65µs under low-VOUT conditions to ensure inductor current decay during fault conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3V ±2% (3.234V to 3.366V), enabling direct replacement of 3.3V LDOs without feedback divider. |
| No-Load Supply Current | 10µA typical, enabling multi-year battery life in always-on sensor nodes and remote monitors. |
| Shutdown Current | 6µA typical, achieved by disabling all circuitry except low-battery comparator and 1.23V reference. |
| Input Voltage Range | 4V to 18V, supporting single-cell LiFePO₄, dual-cell alkaline/NiMH, and wide-range industrial supplies. |
| Peak Switch Current Limit | 325–400mA (RSENSE = 0Ω), setting maximum inductor stress and short-circuit protection threshold. |
| Switch On-Resistance | 1.4Ω typical at VIN = 10V, defining conduction loss and thermal rise under continuous 250mA load. |
| Operating Temperature | –40°C to +85°C (Industrial grade), validated for deployment in automotive cabin electronics and outdoor instrumentation. |
| Efficiency | 92% typical at 250mA, VIN = 10V, VOUT = 3.3V, reducing thermal load and extending runtime in space-constrained devices. |
Pinout & Package
Package: 8-lead plastic SOIC (S8), 150°C/W junction-to-ambient thermal resistance, RoHS-compliant lead-free finish (#PBF).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VOUT/VFB (Pin 1) | Output voltage sense / feedback node | Internally connected to 3.3V divider; provides regulation reference point-no external resistors required for fixed-output version. |
| LBO (Pin 2) | Low-battery comparator open-drain output | Sinks current when LBI < 1.23V; requires external pull-up for microcontroller wake-up or LED indication. |
| LBI (Pin 3) | Low-battery comparator input | Monitors divided battery voltage; functional during shutdown-enables battery monitoring without regulator power. |
| GND (Pin 4) | Power and signal ground reference | Common return for switch, feedback, and comparator circuits; must be low-impedance connection to minimize noise coupling. |
| SW (Pin 5) | Drain of internal P-channel MOSFET | High-slew-rate switching node; requires tight layout to cathode of Schottky catch diode to minimize EMI and voltage spikes. |
| SENSE (Pin 6) | Current sense input | Programs peak switch current via resistor to VIN; omission enables default 325mA limit-no external component needed for basic use. |
| VIN (Pin 7) | Main input supply | Accepts 4V–18V; powers internal bias circuits and gate driver; requires local 0.1µF ceramic + bulk capacitor. |
| RUN (Pin 8) | Logic-controlled enable input | Active-high run control: open/high = enabled, grounded = shutdown; 0.7V threshold ensures TTL/CMOS compatibility. |
Key Features
| Feature | Design Value |
|---|---|
| Burst Mode™ operation | Maintains regulation at light loads with 10µA average supply current-critical for intermittent-sensing IoT endpoints. |
| 100% duty-cycle capability | Supports dropout as low as VOUT – VDS(on); enables stable 3.3V output even when VIN drops to 3.5V, extending usable battery range. |
| Integrated low-battery detector | Remains active in shutdown with 1.23V trip threshold and 5mV hysteresis-provides autonomous battery health monitoring without MCU intervention. |
| Programmable current limit | Adjustable from 10mA to 400mA using single resistor-optimizes inductor size, ripple, and efficiency for specific load profiles. |
| Internal 1.4Ω P-MOSFET | Eliminates external high-side switch; reduces BOM count and PCB area versus controller-based solutions. |
| Industrial temperature rating | Validated performance from –40°C to +85°C-suitable for deployment in uncontrolled environments like factory floor sensors and outdoor telemetry units. |
Applications
| Portable Medical Monitors | Wireless Sensor Nodes |
|---|---|
Use Scenario: Battery-powered ECG front-end with analog signal chain and BLE radio requiring clean, stable 3.3V rail. IC Role / Device Role / Timing Role: Primary 3.3V power supply delivering up to 250mA with ultra-low idle current to maximize battery life between measurements. Use Value: 10µA no-load current extends AA battery life beyond 5 years in sleep mode; 92% efficiency minimizes self-heating near sensitive analog circuitry. | Use Scenario: LoRaWAN environmental sensor node powered by two AA cells, transmitting temperature/humidity every 10 minutes. IC Role / Device Role / Timing Role: Step-down regulator converting 3.0–3.6V battery voltage to regulated 3.3V for microcontroller and RF transceiver. Use Value: 100% duty-cycle operation sustains regulation down to 3.4V input-capturing >95% of battery capacity before cutoff. |
| Handheld Test Equipment | Industrial Data Loggers |
Use Scenario: Pocket-sized multimeter with LCD display, precision ADC, and USB interface operating from 9V alkaline battery. IC Role / Device Role / Timing Role: Main 3.3V supply for digital core and display driver, interfaced with pushbutton ON/OFF via RUN pin. Use Value: 6µA shutdown current prevents battery drain during storage; low-noise Burst Mode™ avoids interference with high-resolution measurements. | Use Scenario: DIN-rail mounted logger acquiring vibration, temperature, and current data in factory settings with 12–24V DC input. IC Role / Device Role / Timing Role: Local 3.3V rail generator for ARM Cortex-M microcontroller and isolated RS-485 transceiver. Use Value: –40°C to +85°C rating ensures reliable startup and operation in unheated enclosures; 18V max input tolerates 24V supply transients. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC1474CS8#PBF | Commercial temperature range (0°C to 70°C); identical electrical specs and pinout. | Not rated for industrial environments; unsuitable for outdoor or factory-floor deployments. | Select LTC1474IS8#PBF when ambient operating temperature may fall below 0°C or exceed 70°C. |
| TPS62231DRVR | Higher switching frequency (3.6MHz), smaller external components, but 25µA shutdown current vs. 6µA. | Optimized for ultra-compact designs; less suitable for multi-year battery life requirements. | Choose TPS62231DRVR only when board space is severely constrained and 6µA shutdown is not critical. |
Compared with LTC1474CS8#PBF, the LTC1474IS8#PBF adds guaranteed operation down to –40°C-essential for cold-climate instrumentation-while matching all electrical parameters. Versus TPS62231DRVR, the LTC1474IS8#PBF trades higher-frequency integration for 76% lower shutdown current, directly extending battery service intervals in infrequently active systems.
Availability
LTC1474IS8#PBF is available at Aetrix Electronics and suitable for portable medical monitors, wireless sensor nodes, handheld test equipment, and industrial data loggers requiring stable component supply across long production lifecycles.
Supply support for LTC1474IS8#PBF includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Analog Devices, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors.
The LTC1474 series was designed specifically for ultra-low-power, battery-operated step-down conversion in portable and industrial instrumentation-emphasizing quiescent current, shutdown integrity, and robustness across wide input ranges.
FAQ
What is the maximum output current capability of the LTC1474IS8#PBF?
The LTC1474IS8#PBF supports up to 250mA continuous output current in typical applications, as validated in the Figure 1 reference design with 100µH inductor and MBR0530 Schottky diode. Peak switch current is internally limited to 325–400mA depending on RSENSE configuration, providing short-circuit protection while maintaining safe thermal operation in the SOIC-8 package at 85°C ambient.
Does the LTC1474IS8#PBF require an external feedback resistor network?
No, the LTC1474IS8#PBF does not require external feedback resistors because it is the fixed 3.3V output version. An internal resistive divider connects VOUT to the 1.23V reference, making Pin 1 (VOUT/VFB) a passive feedback node-no external components are needed for regulation, simplifying layout and reducing BOM cost.
How does the low-battery detection function work on the LTC1474IS8#PBF?
The LTC1474IS8#PBF integrates a dedicated low-battery comparator that continuously monitors voltage at Pin 3 (LBI) against an internal 1.23V reference. When LBI falls below this threshold, Pin 2 (LBO) sinks current in open-drain fashion. Critically, this circuit remains fully operational even during shutdown mode, enabling autonomous battery monitoring without waking the main system.
Can the LTC1474IS8#PBF operate with input voltage below 4V?
The absolute minimum input voltage for reliable regulation is 3.0V per Absolute Maximum Ratings, but the recommended operating range starts at 4V. Below 4V, output voltage may drop out of specification due to reduced gate drive margin on the internal P-MOSFET; the 100% duty-cycle feature sustains regulation down to ~3.4V, but full performance-including 3.3V ±2% accuracy-is guaranteed only from 4V to 18V.
What is the purpose of the SENSE pin on the LTC1474IS8#PBF?
The SENSE pin (Pin 6) on the LTC1474IS8#PBF enables user-programmable peak switch current limiting by connecting an external resistor to VIN (Pin 7). This sets the trip point for the internal current comparator (100mV threshold), allowing optimization of inductor size, ripple, and efficiency. If left unconnected (shorted to VIN), the device defaults to 325mA minimum current limit using its internal sense element.
LTC1474IS8#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down, Step-Up/Step-Down
- Output Configuration:
- Positive or Negative
- Topology:
- Buck, Buck-Boost, SEPIC
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3V
- Voltage - Input (Max):
- 18V
- Voltage - Output (Min/Fixed):
- 1.23V
- Voltage - Output (Max):
- -
- Current - Output:
- 750mA (Switch)
- Frequency - Switching:
- -
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SO
LTC1474IS8#PBF FAQ
1.How can I place an order for LTC1474IS8#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1474IS8#PBF on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for LTC1474IS8#PBF reliable?
The price and inventory of LTC1474IS8#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1474IS8#PBF is usually 5 days.
3.What payment methods are accepted for LTC1474IS8#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1474IS8#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1474IS8#PBF?
LTC1474IS8#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1474IS8#PBF order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LTC1474IS8#PBF?
For technical support, including LTC1474IS8#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1474IS8#PBF requirements.
6.How does Aetrix verify that LTC1474IS8#PBF is sourced from the original manufacturer or authorized distributors?
All LTC1474IS8#PBF products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LTC1474IS8#PBF meets industry standards.
7.What is the process for return or replacement of LTC1474IS8#PBF?
All LTC1474IS8#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1474IS8#PBF, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The LTC1474IS8#PBF part is unused and in its original packaging.
Return procedure for LTC1474IS8#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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